Do not use the fstab parameter on openbsd for mounting (#5805)
Do not use the fstab parameter on openbsd for mounting (#5805)

* Do not use the fstab parameter on openbsd for mounting

OpenBSD's mount command doesn't allow selecting which fstab file to use.
So if we're operating on the live filesystem (mount or remount) return
an error if the user specified an fstab file.

Fixes #5591

* Fix the logic inversion (thanks to @landryb)

thaim/ansible,thaim/ansible